KR20120081687A - Permeable concrete composition using cement and geopolymer binder, and bottom ash aggregate and making method of the same - Google Patents

Abstract

PURPOSE: Concrete using cement, geo-polymer binder, and bottom ash aggregate and a concrete manufacturing method thereof are provided to increase water permeability and bending strength by using bottom ash aggregate. CONSTITUTION: A manufacturing method for concrete is as follows. Water-permeable concrete is injected in a mold. The mold is mounted on a vibrator to be vibrated in 0.5 to 3 minutes for distributing the concrete uniformly. The vibrated mold is hardened in a steam heating chamber in 60 to 90 °C during 1 to 2 hours. The concrete separated from the mold and minimum is cured during 10 hours.

Description

Permeable concrete composition using cement and geopolymer binder, and bottom ash aggregate and making method of the same}

The present invention relates to a method for producing permeable concrete using cement and geopolymer binders and bottom ash aggregates and concrete products thereof. In particular, the present invention relates to the use of cement and geopolymers as binders and bottom ash as aggregates for permeability, strength, The present invention relates to a water-permeable concrete having excellent physical properties such as copper resistance and chemical resistance, and a method for producing the concrete product.

Currently, interlocking blocks, which are widely used for paving roads and plazas, are made of cement concrete products with very low permeability. In rainy weather, most of the rainwater flows along the surface of the road and is drained to the sewers of the road. Therefore, when precipitation increases rapidly at one time and the rainwater is not absorbed underground, flooding of urban areas is frequent. On the other hand, greening blocks, which are installed on the revetment wall on the banks of lakes and roads, require porous and permeable concrete products for plant growth, and also suppress heat island effects and good drainage effects on roads, parking lots, and bicycle paths in parks. Permeable blocks or packaging materials are required to obtain.

Permeable block or road pavement concrete has a relatively weak strength because it uses a coarse aggregate of uniform particle size, unlike the general concrete products. Therefore, it is required to develop a technology for a permeable block or pavement concrete with high compressive and bending strength while maintaining a suitable permeability, and in particular, it is more necessary that their constituent materials are composed of environmentally friendly materials.

Recently, there has been increasing interest in recycling fly ash and bottom ash generated in coal-fired power plants in large quantities, and the effective use of fly ash, which generates about 10 million tons per year, is also required.

The technical details of permeable concrete in concrete using bottom ash aggregate developed in the past are as follows.

In Patent Document 1, 20 to 25% by weight of Portland cement, 2 to 4% by weight of CSA cement, 3 to 6% by weight of fine powder fly ash having a brain particle size of 4,000 to 5,000 cm 2 / g, and a particle size of 4,000 to 5,000 cm 2 / g A water-permeable concrete composition is disclosed comprising blast furnace slag 3-6 wt% and coarse aggregate 60-70 wt% bottom ash having a particle diameter of 5-20 mm.

In addition, Patent Document 2 is composed of 70 to 90 parts by weight of natural aggregates of various colors, 5 to 15 parts by weight of blast furnace slag, 5 to 15 parts by weight of active fly ash, and 2.5 to 7.5 parts by weight of caustic lime. The lower layer is disclosed for a multilayer permeable flat plate consisting of slurry of 2-8 mm and 13-40 mm aggregate sizes, respectively.

In Patent Document 2, since zeolite is produced after curing at high temperature, energy consumption is high, and in order to obtain active fly ash, there is a problem that another heat treatment must be performed, and water-permeable concrete or epoxy or melamine resin using a cement binder is used as a binder. In the used water-permeable block product, there is a problem in that the porous voids of the bottom ash are filled with the resin, thereby decreasing the water permeability and water-retaining property.

In addition, Patent Document 3 discloses a polluted concrete having a bending strength of 50 kg / cm 2 or more using a powdered admixture, a high performance water reducing agent, and water, which are cement, coarse aggregate, and calcium silicate hydrate powder.

In Patent Document 3, there is a disadvantage that the price of calcium silicate hydrate and silica fume is high.

In addition, Patent Document 4, which has a bending strength of 50 kg / cm 2 or more, and a binder composition of in situ permeable concrete having a permeability coefficient of 0.1 cm / sec or more, includes a mixture of silica fume and ulastonite with respect to 100 parts by weight of cement, respectively. Disclosed is a binder for concrete pavement using 32.5 parts by weight, 24 parts by weight.

In Patent Document 4, an expensive admixture such as silica fume is used, and the economical efficiency is questioned. There is a problem that natural aggregates or natural aggregates are used as aggregate without using bottom ash which is waste.

In the new permeable concrete which can improve the low bending strength, which is a disadvantage of the conventional bottom ash as the aggregate, the aggregate is replaced with the bottom ash, and a relatively inexpensive admixture is used in the specification. It is necessary to develop suitable permeable concrete, and when cement is used as a binder, a large amount of CO ₂ is generated during cement production (about 1 ton CO ₂ is produced when producing 1 ton of cement), which is a serious problem for the global environment. It is becoming.

: Republic of Korea Patent No. 0592781 (2006. 06. 18. registration) : Republic of Korea Patent No. 0770152 (2007. 10. 19. registration) : Japanese Unexamined Patent Publication No. 2006-083046 (Published March 30, 2006) Japanese Unexamined Patent Publication No. 2001-181009 (2001.07.03.published)

An object of the present invention is to solve the problems described above, to significantly reduce the amount of cement used as a binder, and to provide a concrete having high permeability and bending strength by using the bottom ash as an aggregate.

The water-permeable concrete according to the present invention for achieving the above object is characterized in that the high performance water-reducing agent and strength reinforcing material is added to the mixture consisting of cement and geopolymer, the bottom ash as aggregate.

In the water-permeable concrete according to the present invention, the cement is Portland cement, the geopolymer is characterized in that the fly ash, alkali silicate and alkali hydroxide or red mud.

In the water-permeable concrete according to the present invention, the geopolymer is characterized in that 60 to 75% by weight of fly ash, 5 to 20% by weight of alkali hydroxide or red mud, 5 to 20% by weight of sodium silicate or potassium silicate.

In the water-permeable concrete according to the present invention, the bottom ash aggregate is characterized in that the aggregate selected in the size of 1 to 3 mm, 3 to 5 mm, 5 to 10 mm.

In the water-permeable concrete according to the present invention, the water reducing agent is characterized in that any one of naphtharic acid, carboxylic acid and potassium phosphate.

In the water-permeable concrete according to the present invention, the strength reinforcing material is characterized in that the organic fibers of acrylic or vinyl, or vegetable fibers obtained by drying and grinding the palm or coconut fruit.

In the water-permeable concrete according to the present invention, the water-permeable concrete is characterized in that 10 to 20% by weight and 5 to 20% by weight of cement and geopolymer as a binder, 60 to 85% by weight of bottom ash as aggregate. .

In the water-permeable concrete according to the present invention, the water reducing agent is added 0.1 to 0.5% based on the amount of the binder used, the strength reinforcing material is added to 1-3% by weight based on 100% by weight of the mixture, the water is water The ratio of / binder is characterized in that 0.15 ~ 0.25.

In addition, the method for producing a concrete product according to the present invention for achieving the above object is injected into the mold, and the mold is mounted on a vibrator, and then vibrated for 0.5 to 3 minutes to uniform the concrete in the mold After the distribution, and the vibration is completed, the mold is cured for 1 to 2 hours at 60 ~ 90 ℃ in a steam heating room, and then demolded to cure at least 10 hours at room temperature.

As described above, according to the method for producing permeable concrete using the cement and the geopolymer binder and the bottom ash aggregate according to the present invention and a concrete product thereof, the amount of cement generated large amount of CO ₂ during production is reduced, and the cement concrete Compared with the low shrinkage ratio and excellent heat resistance, bending strength, freeze resistance, durability, high strength and chemical resistance.

In addition, according to the present invention, a method of producing permeable concrete and its concrete products using cement and geopolymer binders and bottom ash aggregates, using fly ash and red mud generated in large quantities as waste in thermal power plants, Since ash is used as an aggregate, the effect that the manufacturing cost can be greatly reduced is also obtained.

1 is a bottom ash outline photo
2 is a micrograph of a fly ash
Figure 3 is a photograph of a permeable concrete plate and block manufactured using a permeable concrete according to the present invention
4 is a view showing a manufacturing process of a water-permeable concrete product manufactured using water-permeable concrete according to the present invention.

The above and other objects and novel features of the present invention will become more apparent from the description of the specification and the accompanying drawings.

First, the concept of the present invention will be described.

In general, ash is defined as an inorganic material that remains unburned after incineration or combustion of coal or waste. Much of Ash is generated from thermal power plants, but also from waste incinerators, cogeneration plants and other industrial sites as a result of combustion processes. Ash is a recyclable material as an inorganic material (eg SiO ₂ , Al ₂ O ₃ , Fe ₂ O _3, CaO, etc.) in that it is a residue of a combustion product.

When the coal powder is burned, the organics are burned and the inorganics remain as "ash". The ash is agglomerated in a state where it is dispersed in the boiler and attached to the inner wall of the boiler to form a mass. Light and fine particles are collected by an electrostatic precipitator during the exhaust process. The bulk ash attached to the inner wall of the boiler is called "bottom ash" and the ash collected by the dust collector is called "fly ash".

The majority of coal ash is about 85% of the fly ash collected in the dust collector and about 15% of the bottom ash is attached to the inner wall of the boiler and collected on the bottom.

The bottom ash is attached to a wall of a boiler, a preheater, a cutter, and the like, and falls to the bottom of the boiler by a self-weight or load fluctuation damper, is integrated in a hopper, and then crushed and discarded by a grinder.

The bottom ash discarded as described above is observed as a dark gray non-uniform mass, showing a glassy or porous surface, and irregularly shaped particles having an arbitrary size. The main chemical constituents of bottom ash include SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , CaO, MgO, Na ₂ O and K ₂ O. Among the components of the bottom ash, the ratios of silica (SiO ₂ ), alumina (Al ₂ O ₃ ), and iron oxide (Fe ₂ O ₃ ) are 70.0-45.4%, 28.3-15.9%, and 14.32.0%, respectively. Occupies a large amount.

Bottom ash does not contain a large amount of glass paste, such as fly ash, steel slag or smelting slag, but it does contain glass that is sufficient to affect long-term strength.

In addition, as a physical characteristic of the bottom ash, the color of the bottom ash is mostly gray, and has a variety of colors depending on the production environment, ranging from dark yellow to black gray-white. The unburned carbon particles are black in color, while the silica and alumina content is grayish white and yellow in color. Bottom ash does not meet the conditions such as particle shape and chemical composition to serve as a binder.

In addition, the specific gravity of the bottom ash is about 2.1 to 2.7, the dry weight of the bottom ash is 720 ~ 1600 kg / ㎥, plasticity is absorptive, the absorption rate is 2.0% ~ 10.0% is very wide.

Concrete of the present invention is made by adding a water reducing agent and strength reinforcing agents such as acrylic or organic vinyl fiber or palm tree or coconut fruit fiber as a binder and additive of the bottom ash aggregate, inorganic cement and geopolymer, and mixed with water.

The water-permeable concrete using the water-permeable concrete according to the present invention after curing at room temperature to produce a variety of water-permeable concrete products. The permeable concrete product thus prepared has a bending strength of 50 kg / cm 2 or more (according to KSF 4419 Clause 8.1 "Bending Strength Test Method"), and 0.08 cm / sec or more (KSF 4419 Clause 8.4 "Permeability Test) Method ") permeability coefficient).

The bottom ash used in the permeable concrete according to the present invention classifies coal ash, which is crushed and discarded in a thermal power plant, at a particle size of 1 to 15 mm, preferably 1 to 10 mm, and classifies aggregates 1, 3, A bottom ash aggregate of uniform size is used, which is sieved through 5 and 10 mm sieves and the particle size is adjusted to a size of 1 to 3 mm, 3 to 5 mm, and 5 to 10 mm.

The chemical composition of the bottom ash used in the present invention is as shown in Table 1, the external appearance is shown in FIG.

ingredient SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO K ₂ O Na ₂ O TiO ₂ weight% 57.40 26.25 5.67 1.75 0.11 1.68 1.05 0.80

The fly ash used in the present invention is a spherical particle having a size of 20 μm or less collected in an electrostatic precipitator by scattering coal ash generated during coal combustion in a coal-fired power plant, and its chemical composition is shown in Table 2, and its appearance is shown in FIG. 2. As shown.

ingredient SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO K ₂ O Na ₂ O TiO ₂ weight% 52.20 28.90 9.77 0.83 0.30 1.38 0.35 1.98

In addition, the red mud used in the present invention is a strong alkali powdery waste (trade name "Scarlet powder" of KC Corporation) generated in the process of producing alumina hydroxide from the boak side as a via process, the particle size is 10㎛ or less Having a size, the chemical composition is as shown in Table 3.

ingredient SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO K ₂ O Na ₂ O TiO ₂ weight% 20.30 22.40 15.50 8.90 0.30 0.03 11.00 6.67

On the other hand, the strength reinforcing material uses organic fibers such as acrylic or vinyl, or vegetable fibers obtained by drying and grinding palm or coconut fruit.

The amount of the strength reinforcing material is added in an amount of 0.1 to 5.0% by weight, preferably 0.2 to 2.0% by weight, based on 100% by weight of the composition of the cement and geopolymer binder and the bottom ash aggregate used in the present invention.

The reducing agent uses naphtharic acid, carboxylic acid or potassium hydrogen phosphate, and 0.1 to 0.5% is added to the amount of the binder composed of cement and geopolymer.

The ratio of water / binder is 0.15 to 0.25.

The geopolymer used in the present invention is composed of fly ash, alkali hydroxide, alkali silicate, alkali hydroxide uses sodium hydroxide, potassium hydroxide or red mud, and alkali silicate uses sodium silicate, potassium silicate. The mixing ratio is used that consists of fly ash, 60? 75% by weight, alkaline oxides (NaOH) or red mud 5? 20% by weight, sodium silicate _{(Na 2 SiO 3) 5?} 20% by weight.

The water-permeable concrete according to the present invention is composed of a mixture of cement and geopolymer 10 to 20% by weight, 5 to 20% by weight, and bottom ash 60 to 85% by weight as aggregate, and the water reducing agent is cement and geo 0.1 to 0.5% of the amount of polymer used, strength reinforcing material is added by 1 to 3% by weight of organic fibers relative to 100% by weight of the binder and aggregate mixture, and water is added so that the ratio of water / binder is 0.15 to 0.25.

In the concrete, when the amount of cement and geopolymer as binder is less than 10% by weight and 5% by weight, respectively, the coefficient of permeability is excellent but the bending strength decreases, and the amount of cement and geopolymer is 20% by weight, respectively. When it exceeds, the bending strength increases but the permeability coefficient decreases. Accordingly, the amount of cement and geopolymer having a desirable coefficient of permeability and bending strength is preferably 15-18% by weight of cement and 10-15% by weight of geopolymer.

On the other hand, when the ratio of water / binder is less than 0.15, the adhesion force to which the binder adheres to the aggregate surface is reduced, and when it exceeds 0.25, the bending strength decreases. Therefore, the amount of water is preferably 0.15 to 0.25, and most preferably 0.20 to 0.23.

The bottom ash aggregate used here uses the thing sorted by the magnitude | size of 1-3 mm, 3-5 mm, 5-10 mm.

Table 4 shows the results of investigating the physical properties of the water-permeable concrete product while changing the mixing ratio of the water-permeable concrete composition.

division Binder (% by weight) Bottom ash aggregate (% by weight) additive
compression
burglar
(Kg / cm2)
flex
burglar
(Mpa)
Permeability coefficient
(Cm / sec) cement Geo
Polymer ^{1 )}
1-3mm
3-5 mm
5-10 mm Reducing Agent ^{2 )}
(%) fiber
Reinforcement ^{3 )}
(weight%) Example 1 20 20 10 25 25 0.2 1.0 320 5.3 8 x 10 ^-2 Example 2 15 20 10 25 30 0.2 1.0 300 5.0 1.5x10 ^-1 Example 3 10 15 10 33 32 0.2 1.0 280 4.5 3.5 x 10 ^-1 Example 4 10 10 17 31 32 0.2 1.5 220 3.9 8.0x10 ^-1 Example 5 10 5 17 36 32 0.2 1.5 230 3.0 8.5 x 10 ^-1 Example 6 15 15 10 28 32 0.2 2.0 310 5.4 2.0 x 10 ^-1 Example 7 20 15 10 30 25 0.2 2.0 330 5.4 9.0x10 ^-2 Comparative Example 1 20 - 12 36 32 0.2 - 180 2.8 8.0x10 ^-1 Comparative Example 2 30 - 10 28 32 0.2 - 200 3.0 6.0 x 10 ^-1 Comparative Example 3 40 - 10 20 30 0.2 - 230 3.5

Note 1) Geopolymer binder: fly ash 70% by weight, red mud 20% by weight, Na ₂ SiO ₃ 5% by weight, NaOH 5% by weight

  2) Reducing agent is the ratio of binder usage

  3) Strength reinforcing material is added amount to 100% by weight of the mixture consisting of the binder and aggregate

4) The width, length and height of the test specimen are rectangular parallelepipeds of 220 * 110 * 80㎜.

Hereinafter, the manufacturing process of the water-permeable concrete product of the present invention will be described with reference to FIG.

Figure 4 is a view showing a manufacturing process of a water-permeable concrete product manufactured using water-permeable concrete according to the present invention.

First, 0.1 to 0.5% of a water reducing agent is added to a mixture consisting of 10 to 20% by weight cement, 5 to 20% by weight of geopolymer and 60 to 85% by weight of bottom ash aggregate, and 100% by weight of the mixture. 1 to 3% by weight of organic fibers are added, and water is added so that the ratio of water / binder is 0.15 to 0.25, and then mixed concrete is prepared (S10).

Injecting the concrete mixed in the step S10 into a mold of a predetermined size, and mounted on the vibrator mold, the concrete is injected, preferably 0.5 to 3 minutes, more preferably 1 to 2 minutes to vibrate within the mold The concrete is uniformly distributed to have a shape (S20).

The form used here is a form for manufacturing the flat plate or block shown in FIG. Since the shape can be variously changed according to the pavement, sidewalk, parking lot, bicycle path, etc., the shape inside the form is not particularly limited.

The mold in which the vibration is completed in step S20 is cured in a steam heating chamber at 60 to 90 ° C. for 1 to 2 hours, preferably at 60 ° C. for 1 hour (S30).

The concrete product such as a block or a plate hardened in the step S30 is demolded from the mold (S40). The demolding timing can be changed depending on the size, height, etc. of the mold, but is preferably performed when the temperature has dropped to a normal temperature.

The demolded concrete product is cured for at least 10 hours, more preferably one week at a place of normal temperature well ventilated without direct sunlight (S50).

The compressive strength, bending strength and permeability coefficients of the test bodies thus prepared are shown in Table 3.

As mentioned above, although the invention made by this inventor was demonstrated concretely according to the said Example, this invention is not limited to the said Example and can be variously changed in the range which does not deviate from the summary.

The present invention uses the bottom ash, a solid waste generated from coal-fired power plant as aggregate, and by using a geopolymer using fly ash as a raw material as a binder, it can be utilized in the industrial field of recycling coal ash, geopolymer By using the binder together with cement, it can be utilized in the environment-friendly field to drastically reduce the global carbon generation.

In addition, it is possible to produce a product having a chemical resistance, in particular acid resistance, explosion resistance, low shrinkage rate, which is a disadvantage of cement concrete products, it can be utilized in the construction of sound-absorbing materials (soundproof walls), acid-resistant waterway pipes, electric poles, structures of building materials.

Claims (9)

A water-permeable concrete comprising a mixture of cement, geopolymer as a binder, and bottom ash as aggregate, by adding a high performance water reducing agent and a strength reinforcing material. The method of claim 1,
The cement is Portland cement, wherein the geopolymer is fly ash, alkali silicate and alkali hydroxide or red mud permeable concrete. The method of claim 2,
The geopolymer is 60 to 75% by weight of fly ash, 5 to 20% by weight of alkali hydroxide or red mud, and 5 to 20% by weight of sodium silicate or potassium silicate. The method of claim 2,
The bottom ash aggregate is permeable concrete, characterized in that the aggregate selected in the size of 1 ~ 3mm, 3 ~ 5mm, 5 ~ 10mm. The method of claim 2,
The water reducing agent is water permeable concrete, characterized in that any one of naphtharic acid, carboxylic acid and potassium phosphate. The method of claim 2,
The strength reinforcing material is a water-permeable concrete, characterized in that the organic fibers of acrylic or vinyl, or vegetable fibers obtained by drying and grinding palm or coconut fruit. 7. The method according to any one of claims 1 to 6,
The water-permeable concrete is a water-permeable concrete, characterized in that the cement and geopolymer 10 to 20% by weight and 5 to 20% by weight as a binder, the bottom ash 60 to 85% by weight as aggregate. 8. The method of claim 7,
The water reducing agent is added 0.1 to 0.5% based on the amount of the binder, the strength reinforcing material is added to 1 to 3% by weight based on 100% by weight of the mixture, the water is characterized in that the water / binder ratio of 0.15 to 0.25 Permeable concrete. The water-permeable concrete according to claim 7 is injected into the mold, and the mold is mounted on a vibrator. The mold is vibrated for 0.5 to 3 minutes to uniformly distribute concrete in the mold, and the mold is subjected to steam heating. A method of producing a water-permeable concrete product, which is cured at 60 to 90 ° C. for 1 to 2 hours in a room, followed by demolding and curing at room temperature for at least 10 hours.

Images